# CVE-2020-9321: Traefik has an Improper Certificate Handling issue

> Traefik fails to purge certificate contents from providers before logging, potentially exposing sensitive certificate data in logs.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Mar 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-7h6j-2268-fhcm, GO-2022-0808

## What is CVE-2020-9321?

CVE-2020-9321 is a high-severity vulnerability in Traefik Traefik, published on 16 Mar 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

configurationwatcher.go in Traefik 2.x before 2.1.4 and TraefikEE 2.0.0 mishandles the purging of certificate contents from providers before logging.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2020-9321?

5 open source packages ship an affected version, including github.com/traefik/traefik, github.com/containous/traefik and github.com/containous/traefik/v2. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/traefik/traefik` | Go | All versions | None |
| `github.com/traefik/traefik` | Go | All versions | 2.1.4 |
| `github.com/traefik/traefik` | Go | All versions | 2.1.4 |
| `github.com/containous/traefik` | Go | All versions | None |
| `github.com/containous/traefik/v2` | Go | All versions | 2.1.4 |

Products: Traefik Traefik, Traefik Traefik Enterprise.

## How do I fix CVE-2020-9321?

Upgrade github.com/traefik/traefik to 2.1.4 or later.

## Is CVE-2020-9321 being exploited?

There is no known exploitation of CVE-2020-9321 in the wild and no public exploit code.

## Other vulnerabilities in Traefik Traefik

- [CVE-2024-45410](https://insights.sbomify.com/CVE-2024-45410/): HTTP client can remove the X-Forwarded headers in Traefik (critical 9.8)
- [CVE-2026-88877](https://insights.sbomify.com/CVE-2026-88877/): Traefik v3.7.0 Authentication Bypass via from-to-www-redirect (critical 9.3)
- [CVE-2026-85595](https://insights.sbomify.com/CVE-2026-85595/): Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth (critical 9.3)
- [CVE-2026-88007](https://insights.sbomify.com/CVE-2026-88007/): Traefik HTTP/3 Backend NTLM Connection Reuse (critical 9.1)
- [CVE-2026-88009](https://insights.sbomify.com/CVE-2026-88009/): Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-9321 and fix it if it is affected.

What it is: CVE-2020-9321 is a high-severity vulnerability in Traefik Traefik, published on 16 Mar 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-9321 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/traefik/traefik (Go): affected all versions; no fix listed
- github.com/traefik/traefik (Go): affected all versions; fixed in 2.1.4
- github.com/traefik/traefik (Go): affected all versions; fixed in 2.1.4
- github.com/containous/traefik (Go): affected all versions; no fix listed
- github.com/containous/traefik/v2 (Go): affected all versions; fixed in 2.1.4

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-9321/ (Markdown: https://insights.sbomify.com/CVE-2020-9321/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-9321
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-9321
- OSV: https://osv.dev/vulnerability/CVE-2020-9321

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-9321/
Summaries are generated and may contain mistakes; the official description above is the record.